[6] Loh's success as a child in Penang state team saw him receive a scholarship from the Singapore Sports School.

[7] Loh's elder brother, Kean Hean, is also a member of the Singapore national badminton team.

[7] He stopped playing the sport at age seven after being looked down on by his seniors, in contrast to media reports which stated that he had been "bullied" as a child.

[18] Loh was also offered a place in Malaysia's Bukit Jalil Sports School but he rejected it for Singapore.

[18] From late 2011 onwards, Loh was coached by Kelvin Ho, a former Singapore national badminton player.

[7][21] His mother said that the family was "shocked", and recounted telling Loh: "I sent him to Singapore to study, but now he wants to give that up to play badminton?

139) represented Singapore at the 2015 SEA Games in the men's singles event and won a bronze after being defeated by Mohamad Arif Abdul Latif in the semi-final.

[26][36] Loh served his National Service (NS) for the Singapore Armed Forces (SAF) from 2016 to 2018, eventually earning the rank of corporal first class (CFC).

[42] During the Thailand Masters in 2019, as a qualifier, Loh won against China's Zhou Zeqi, Zhao Junpeng, and Chinese Taipei's Wang Tzu-wei before advancing to the semifinals.

[43] At Loh's first World Championships, he lost to Chinese Taipei's Chou Tien-chen in the round of 16, losing 13–21, 21–18, 17–21 in three games.

[44] Loh won the men's singles silver medal in the 2019 SEA Games, losing in the final match against Lee Zii Jia of Malaysia.

[45] Loh also won his first National Championships title that year, defeating compatriot Lee Wei Hong in the final.

[46] Loh qualified for the 2020 Summer Olympics after placing 18th in the Race to Tokyo men's singles rankings.

[49][50] From August 2021, Loh attended a one-month training camp in Dubai arranged by Denmark's Olympic badminton champion Viktor Axelsen, joining Axelsen and fellow players Toby Penty from England, Brian Yang from Canada, Felix Burestedt from Sweden, Lakshya Sen from India, as well as teenagers Axel Parkhoi and Marcus Viscovich from Denmark.

[61] His run was the best performance by a Singaporean male shuttler since Ronald Susilo's singles win at the 2004 Japan Open, a Super 750 tournament.

[68][69] After the semi-final match, Loh's right ankle injury had deteriorated to the point that he could not walk and required a wheelchair.

[17] His return to Singapore's Changi Airport was greeted with a water salute at the tarmac, similar to Joseph Schooling after he had won a gold medal at the 2016 Summer Olympics in swimming.

[4] Loh started the season with a defeat in the final of the India Open to Lakshya Sen in straight games, with a score of 22–24, 17–21.

[72] Loh then fell in the first rounds of the German and All England Open, where he lost to Brian Yang and Anders Antonsen respectively, both in 3 games.

[75][76] In his first Thomas Cup appearance, Loh played well, winning all his matches as the first singles, beating Indonesia's Anthony Sinisuka Ginting (21–13, 21–14), South Korea's Heo Kwang-hee (21–14, 21–12) and Thailand's Khosit Phetpradab (21–15, 21–18) in straight sets to earn the points for Singapore in every series.

[77] At the 2021 SEA Games in Vietnam, Loh entered the men's team event, playing the first singles for Singapore.

[80] Loh then rose back to his then career-best ranking of 9th place the next week, overtaking India's Lakshya Sen.

[86] In the first week of October, Loh rose to his then career-rank high of 5, replacing Kento Momota, who fell 2 spots after an update of ranking points.

[88][89] However, Loh lost in the semi-finals to Malaysia's Lee Zii Jia in straight games the next day, losing 18–21, 15–21 in 39 minutes.

After defeating Shi Yuqi and Shesar Hiren Rhustavito in the first and second round, Loh crashed out to 5th seed and eventual winner Anthony Sinisuka Ginting in the quarterfinals, losing in straight games, 13–21, 14–21.

[93] In his second encounter with Jonatan Christie, Loh lost in three games, 21–16, 20–22, 10–21, failing to convert his 2 match points in the second set.

[98] Loh crashed out of the Badminton Asia Championships 2024 in the first round, failing to repeat his 2023 run where he reached the final.

[101] In the Round of 16, Loh upset China's world number 6 Li Shifeng in straight sets, 23-21, 21-15, booking a spot in the quarterfinals.

Loh unfortunately lost the quarterfinal to the eventual Olympic gold medalist and world number 2, Dane's Viktor Axelsen.

[103] Loh's initials, LKY, has been noted by Singaporeans as being identical to Lee Kuan Yew, Singapore's first prime minister and its founding father.